On Tue, Feb 02, 2010 at 02:37:41AM -0800, Guenter Roeck wrote:
Pretty good, let the nitpicking start :-)
> diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
> index 1f4df64..284eb55 100644
> --- a/arch/mips/include/asm/cpu-features.h
> +++ b/arch/mips/include/asm/cpu-features.h
> @@ -209,6 +209,9 @@
> # ifndef cpu_has_64bit_addresses
> # define cpu_has_64bit_addresses 1
> # endif
> +# ifndef cpu_vmbits
> +# define cpu_vmbits cpu_data[0].vmbits
> +# endif
> #endif
For 32-bit kernels we probably should fix cpu_vmbits to 31.
#ifdef CONFIG_64BIT
# ifndef cpu_vmbits
# define cpu_vmbits cpu_data[0].vmbits
# define __NEED_VMBITS
# endif
#else
# #define cpu_vmbits 31
#endif
> #if defined(CONFIG_CPU_MIPSR2_IRQ_VI) && !defined(cpu_has_vint)
> diff --git a/arch/mips/include/asm/cpu-info.h b/arch/mips/include/asm/cpu-info.h
> index 1260443..3c694bc 100644
> --- a/arch/mips/include/asm/cpu-info.h
> +++ b/arch/mips/include/asm/cpu-info.h
> @@ -58,6 +58,7 @@ struct cpuinfo_mips {
> struct cache_desc tcache; /* Tertiary/split secondary cache */
> int srsets; /* Shadow register sets */
> int core; /* physical core number */
> + int vmbits; /* Virtual memory size in bits */
#ifdef __NEED_VMBITS
int vmbits; /* Virtual memory size in bits */
#endif
To do for a later separate patch - minimize the sizes of all cpuinfo_mips
members; int is overkill for many members.
> #if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_MIPS_MT_SMTC)
> /*
> * In the MIPS MT "SMTC" model, each TC is considered
> diff --git a/arch/mips/include/asm/pgtable-64.h b/arch/mips/include/asm/pgtable-64.h
> index 9cd5089..8eda30b 100644
> --- a/arch/mips/include/asm/pgtable-64.h
> +++ b/arch/mips/include/asm/pgtable-64.h
> @@ -110,7 +110,9 @@
> #define VMALLOC_START MAP_BASE
> #define VMALLOC_END \
> (VMALLOC_START + \
> - PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE - (1UL << 32))
> + min(PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, \
> + (1UL << cpu_vmbits)) - (1UL << 32))
> +
This overlaps with other allocations near the top - yes, we've been living
dangerous but with bottom up allocations a conflict was very, very unlikely.
Dealing with them in a sane way in the VMALLOC_END macro definition is hard,
so I suggest changing the definition to something like:
extern unsigned long vmalloc_end;
#define VMALLOC_START MAP_BASE
#define VMALLOC_END vmalloc_end
And initialize the value of vmalloc_end in something like the mm section of
arch/mips/kernel/traps.c:per_cpu_trap_init().
There you can also ensure the value of vmalloc_end is <= FIXADDR_START.
Finally probing can be used to fix yet another sin. For 64-bit kernels
arch/mips/include/asm/processor.h defines TASK_SIZE:
#define TASK_SIZE 0x10000000000UL
This should turn into something like.
#define TASK_SIZE (1UL << vmbits)
This is also why I sugget to keep vmbits as 31, not 32. Hello S390 :-)
> +static inline void cpu_set_vmbits(struct cpuinfo_mips *c)
> +{
> + if (cpu_has_64bits) {
> + write_c0_entryhi(0x3ffffffffffff000ULL);
> + back_to_back_c0_hazard();
> + c->vmbits = fls64(read_c0_entryhi() & 0x3ffffffffffff000ULL);
> + } else
> + c->vmbits = 32;
> +}
With my changes suggested above this would need changing to something like:
static inline void cpu_set_vmbits(struct cpuinfo_mips *c)
{
if (__NEED_VMBITS) {
write_c0_entryhi(0x3ffffffffffff000ULL);
back_to_back_c0_hazard();
c->vmbits = fls64(read_c0_entryhi() & 0x3ffffffffffff000ULL);
return;
}
BUG();
}
> #define R4K_OPTS (MIPS_CPU_TLB | MIPS_CPU_4KEX | MIPS_CPU_4K_CACHE \
> | MIPS_CPU_COUNTER)
>
> @@ -967,6 +977,8 @@ __cpuinit void cpu_probe(void)
> c->srsets = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
> else
> c->srsets = 1;
> +
> + cpu_set_vmbits(c);
I think a name like cpu_probe_vmbits() would be clearer.
Thanks,
Ralf
